Locking pliers



June 28, 1960 J. J. BANNISTER 2,942,503

LOCKING PLIERS Filed Sept. 17, 1957 2 Sheets-Sheet x INVENTOR.

John J Bum/yer BY his oliomeys June 28, 1960 J. J. BANNISTER LOCKING PLIERS Filed Sept. 17, 1957 2 Sheets-Sheet 2 I NV EN TOR. John J Banm'sfer BY MS affomeys 'jus tably restricting United States Patent LOCKING PLIERS John J. Bannister, so co s St., Newark, NJ. Filed Sept. 17, 1957, Ser. No. 684,582

6 Claims. (c1. 81-330) This invention relates to pliers, and more particularly to locking pliers whereby the jaws may be locked in a clamping position on the work.

In this preferred embodiment, this invention relates to locking parallel jaw pliers.

Various forms of locking pliers have been provided,

' .2 Fig; 6 is a" front elevation illustrating a form of center block used in the pliers in Fig. 1, 2 and- 3.

;;Fig. 7 is a sectional view taken along the line 7--7 ofFig. 6. p I

.Fig. 8- is a view of ,a screw and pin assemblyused in the pliers of Figs. 1, 2 ,and 3. Fig. 9 is a front elevation of. a simple form of locking pliers havingtwo 'distinctjaw pivot positions. Fig. 10 is a side view of the pliers in Fig. 9. Fig. 11 is a front elevation ofthe pliers of Fig. 9 and 10 illustrating. the jaws in an alternate positional adjustment.

and most of these forms are rather involved structurally,

and frequently do not provide a satisfactory locking grip.

In addition, difiiculty, has been experienced'in unlocking certain of these pliers when in use. Locking pliers have proven to be particularly valuable when the pliers are used as an adjustable wrench.

In this connection, locking pliers provide a better adjustment as well as. an absolute grip. Accordingly, it is particularly important to havefihe jaws substantially par,- allel in the desired width for achieving good operation as a wrench.

It is therefore provide a simplified and improved form of locking pliers which is smooth inloperation and yet provides an excellent grip. i

Another object to the length of the pliers and equidistant from their closed position. 4

A further object of this invention is' to provide a form of locking pliers in which the jaws are adjustable to two positions forv handling comparatively wide and narrow objects. i

A still further object of this invention is to provide a pair of locking pliers having easily removableparallel jaws so that various different type jaws may be used with a single set of pliers for utilization in a variety of jobs.

The important-feature of my invention is a center block and means for restricting movement of the center block in combination with pivotal handles and jaws generally provided in apairof pliers. The center block is operatively connected with the handlesin a manner which positively provides that. the axial movement of the center block and the. pivotal motion 'of the handles are .mutually dependent; In addition, means are provided for adthe movement of the center blockwith respect to the pivot pin in In addition to this function, 'the center block is used in the preferred embodiment of this invention to provide parallelism in the jaws ofthe pliers;

In the drawings wherein like numerals are given to illustrate like parts tliroughoutz Fig. 1 is a front elevational view of 'a pair of. parallel 'jaw -lockingfpliers shown in an open'positi'on'fenibodying Fig. 3 jis a side new of the pliers or Figs 1 and 2.

Fig. 4 is a prospective view of a handle of the pliers of Figs."l,12.and3. w pp A Fig. 5 is a prospective 'view of one jaw of the pliers of Figs. 1, 2 and of this invention is to provide a form t of locking pliers in which the jaws are always parallel a primary object of this invention to jaws.

. piers of Figs. 9,10 and 11,

Fig. 12 is a prospective view of the centeriblock used in thepliers of Figs. 9, 10 and 11. f v j Fig. 13 is a prospective view of thecollarnsed in the Fig. l4 is an isometric view of the adjustment assembly utilized in the pliers of Figs. 9, l0 and 11..

Fig. 15 is a partial front elevation of the two jaws and center block of the pliers in Figs. 9-11 illustrating a relative position of these parts. h -Fig.- 16 is a [front elevation of a simple form of locking wire-cutter pliers embodying the broad aspect of this invention.

Referring more particularly to Figs l-S, .rny pliers have the usual crossedhandlesf 21 which, if desired, may be made of sheet metal as illustrated in Fig. 4. The

handles 21 are hingedly connected at their crossings by a pivot pin 22 which fits through the holes 23 of the handles 21. '1he forwarder projecting ends 24 ,of :the

handles "have holes 25 provided therein. to receive jaw pivot pins 26 A-pair of jaws 27 are provided whichmay have the conventional shape of plier jaws, if desired,.and

also contain elongated slots 28 as shown in Fig. 5 :for receiving the jaw pivot pins 26. a The slots 28 have the same width as the pivot pins 26 so that axial movement ormovementlengthwise of the pliers is allowed while movement perpendicular to the axis of the pliers is positively prevented.

It willbe obvious that closing the back ends of the.

handles will cause the jaw pivot pins to come together, I

close the pliers and apply pressure to any work in the :sure by-the jaws, the parts hereinafter described being providing the desired. lock. i

primarily for locking the pliers in position and in this embodimentfor maintenance of parallelism.

i .In the form of the invention illustrated in Figs. 1-8, there is providedipliers having thedouble ability of looking jaws and maintenance of parallelism no matter whether the pliers are open or shut, and whether ornot the jaws are in contact with any work in the pliers. For this purpose, I provide a special center block 29 (see Figs. 6 and 7) which has an elongated slot 30 of a width corpivot pin 22 and adapted to allow thecenter block 291 pivot pin 22 but restricted from lateral motion; It

now apparent that the pair ofhandles 21.are crossed so that their central pivotholes 2 3 arein alignment, and

the center block??? is fittedltherebetween with its central slot 30 in alignment with holes'23. The central pivot 'pin 2.2'is1then fit through the aligned holes andsecured therein by conventional' means such or the"lil-:e

i The centerblock 29 alsolcontains apair of angular-ly disposed slots 31 as shown in Fig.,,6 which are aligned.

with holes 32 providedin handles 21.: With the slots. andv have a w t corresponding .to'thewidth of'the slots 311m holes 32 are insertedtherethrough and secured by bolting, riveting, f These pins serve to prevent rotative movement of the center block 29' and alsotoa.

holes in aligment, guide pins ;33 which cotter keys or the like.

provide that the pivotal motion of theharidles andtaxial} This is the real source of movement of and pres-' to slide axially along the as riveting, bolting Accordingly,

.with the pin 42' movement ofthe center block be mutually dependent.

If desired, lugs may be provided on handles 21, to servethe same function as guide pins 33 fitting in holes 32. It is also obvious that the parts may be reversed, i.e. lugs may be provided on the center block which would fit into slots on the handle.

To keep the jaws parallel no matter whether the-pliers are open or shut, there is provided a pair of angularlydisposed grooves 34 on the center block 29 and corresponding angularly-disposed tongues 35 of the'jaWs 27. These angularly-disposed grooves 34 are substantially parallel to the slots 31 so that axial movement of the center block provides the same inward or outward motion to the tongues 35, or rear end of the jaws- 27 as isprovided to the guide pins 32 that are secured within the handles 21.

It is thus seen that as the handles- 21 are pivoted relatively towards one another, as in moving the handles from the position illustrated in Fig. l to the position illustrated in Fig. 2, the guide pins 32 move within the slots 31 causing the center block 29 to move axially away from the jaw end of the pliers by virtue of the-slot 30 sliding with respect to the central pivot pin 22 which in turn causes the tongues 35 to slide within the grooves 34 thereby positioning the base end of the jaws closer together as shown in Fig. 2 while the forward end of the handles 21 imparts motion to the central part of the jaws 27 through the jaw pivot pins 26 thereby providing the closing movement of the jaws. Similarly, on opening of the jaws, the jaw ends of the handles are spread apart thereby moving the'jaws relatively apart while the guide pins 32 cause the center block 29 to move axially toward the jaws with the relative movement of'tongues 35 within 'grooves 34 to maintain parallelism for all positions. Since the movement of the tongues 35 in slight axial movement to the jaws with respect to the handles 21, slots 28 are elongated to allow such movement to take place.

From the foregoing it is seen that the center block acts as an intermediate part to positively maintain parallelism and that the axial movement of the center block and pivotal movement of the handles are mutually dependent, i.e. one cannot take. place without the other; Therefore, I have provided a combination of mechanical parts which will provide a lock on the pivotal motion of the handles and jaws of the pliers by locking. the axial movement of the center block. Since the work itself grooves 34 imparts a prevents further closing of the jaws of the pliers, it is onlynecessary to provide means for preventing the opening of the jaws of the pliersin order to achieve a lock. since the opening of the pliers requires that the center block move axially toward the jaw end of the pliers, I have provided means to prevent this movement thereby providing. a positive lock.

In the pliers illustrated in Figs. 1-8, the center block 29 contains a hole 36 which extends axially to the slot 30. Also extending along the bore or hole 36 is a keyway 37 which is preferably provided on both sides of the bore. There is also provided a rectangular opening 38 having dimensions sutficient to slide the knurled nut 39' (Figs. 1 and 2) therein with the central opening of the nut being in alignment with the center line of bore 36. In addition, there is provided a laterally-extending bore 40 in center block 29 as shown in Figs. 3 and 6. In

addition to the structures on the center block, the lock means in the pliers of Figs. 1-8 comprises the screw 41 which has stop pin 42 laterally extending therethrough corresponding in dimensions with the keyway 36 and the screw 41 adapted to fit threadably within the nut 39., The screw 41. also has a surface 43 adapted to abut the central pivot pin 22'.

When assembling the locking mechanism, the screw '41.without stop. pin 42. is threaded through the nut 39 intotherbore r36. The. hole. in-screw 41, in whiclnstop pin 42.fits. isealignedwith. bore. .40: and pirr142 is inserted therethrough and into position in keyway 37. Upon further turning of nut 39, screw 41 advances within bore 36 because stop pin 42 prevents rotation of the screw. When the screw is brought down all the way, the stop pin 42 rests on top of the nut 39 and serves as a stop against further movement of the screw. In this position (position of Fig. 1), the pliers may be opened and closed freely. The pliers may he closed by closing of the handles or, if desired, by, means of rotation of the nut 39. in Fig. 2, with the-screw brought up against the central? pivot by meansof. the. nut. 39, the angular slots 31 are drawn down on lower guide pins 33 due to the bottom of the not bearing-onthe plate, the handles are drawn closer together and clamping. action is placed on the jaw by means of the handles.

The nut 39 may be cross drilled with a hole 44 so that a pin may be inserted therein to obtain greate" leverage, if desired. When locking the pliers in position over the nut or bolt, pressure may be applied both by means of closing pressure on the jaws of the handle 21 and clamping pressure by rotation of nut 39. It is thus apparent that I have provided an improved form of locking pliers which provides improved clamping pressure as well as jaw parallelism ina comparatively simple and durable mechanism;

Another advantage of the pliers illustrated in Figs. 1-8 resides in the fact that the design illustrated allows for simple changing of jaws. The jaws may be removed by simplyremoving the jaw pivot pins 26 and sliding the jaw out of engagementwith the center block. It is apparent that the essential features of the jaw fitting the parallel locking pliers of this invention include the morticed tongues 35 and-the elongated pivot hole 28 include. jaws for gripping pipe or cutting tools (i.e. one

jaw with two roller supports and the other. jaw having a circular cutter). In addition, the jaws may have parallel outside surfaces and .be suitable as an internal clamp to force two surfaces apart and keep them in a spread position. In such a situation the clamping force is applied in the reverse direction and this may be accomplished by attaching the screw 41. to the central pivot 22. Therefore, one pair of pliers and a set of various jaw pairs can provide a single tool with many uses In Figs. 9-15; there is illustrated a pair of two position pliers which contains the features incorporated in the pliers popularly sold on the market in combination with the novel mechanism of this invention for locking the pliers. Accordingly, the pliers in this embodiment comprises crossed handles 51 and 52 pivotally attached at their crossing central pivot pin 53. The handle 52 has a jaw 54 integrally attached thereto, a central pivot hole 55 through which central pivot pin 53 fits, and a hole 56 located toward thehandle end from .thecentral pivot hole 55. The handle 51 contains. a jaw 57 integrally attachedthereto which parts are similar in size and shape to handle 52 and jaw 54. Thus, as in the case of the embodiment of.Figs. 1 to 8, the handlesare operatively connected to the jaws. However, the handle 51 contains a pair of central pivot holesv 58 and 59. as best. seen in ,Fig, 15 with a slot 60 extending therebetween. The

central pivot pin 53 fits in the bore 55 of handle 52 and also. in the hole 53 or 59 of the handle 51. The pivot pin 53 is flattened to,- allow it to fit through the slot 60 connecting the twocircular. bores or holes 58 and 59. Allof the parts 51 to 60 except the hole 56 are con- The center block 63 is having a screw 64 extending externally from the middle of one side and which extends axially along the pliers whenthe center block is in position. The center block '63 also contains a central slot 65 having the same width as pivot pin 53 and angularly extending slots 66 and 67. When in position on the pliers, the central slot 65 has pivot pin 53 extending therethrough and the slot 66 is aligned with hole 56 of handle 52 while 67 is aligned with either the hole 61 or 62 of handle 51 as will be described below.

Fitting within the hole 56 of the handle 52 is a guide pin 68 having a width of and slidably fitting within the slot 66 of the center block 63. As explained in the parallel jaw embodiment above, the guide pin 68 and hole 56 may be a lug integral with the handle 52and fitting Within the slot 66. However, it is important that when either a pin or lug is used the length thereof be short enough that it does not extend beyond the upper surface of the center block 63 and interfere with jaw movement when the pliers are in the adjusted position shown in Fig. 11.

The guide pin which fits through either the hole 61 or 62 of handle 51 is rendered adjustable so that when the central pivot pin is positioned within hole58 the guide pin fits in hole 61, and when the central pivot is positioned within hole 59 the guide pin fits in hole 62.

' The adjustment assembly for achieving this function is shownin Fig. 14 wherein a guide pin 69 is shown fitting within a frame 70. The frame 70v has a hole 71 at one end adapted to fit around the central pivot pin 53 and a hole 72 having the diameter of holes 61 and 62 and having its center located at a distance from, the center of hole 71 which corresponds to the distance of the center of hole 61 from the center of hole 58. Frame 70 also has a recess 73 which contains spring 74 and stop 75. Guide pin 69 comprises a head 76 and a slot 77 as shown in Fig. 14. The spring stop 75 is retained withinslot 77' to prevent guide pin 69 from falling out of the pliers. When in position, the guide pin 69 fits within slot 670i center block 63 and is adjusted to extend through hole 61 when the central pivot pin is adjusted within hole 58 and extends through hole 62 when the central pivot is adjusted Within hole 60.

The adjustable pin assembly not only serves to provide the desired relationship of movement between the pivotal motion of the handles and the center block, but also serves to prevent the central pivot pin from inadvertently moving from hole 58 to 59 or the reverse as frequently happens in conventional pliers.

a triangularly-shaped plate also provided a collar 78 which operates in combination with center block 63. This collar has a base 79 and a pair of flanges 80 and 81. The base 79 has a hole 82' in the center thereof, which is larger than the screw 64 of the center block 63. The flanges 80 and 81 have holes 82 and 83 which are of a size sufiicient to allow the pivot pin 53 to fit therethrough.

In order to assemble various parts, the center block 63 is placed between the handles 51 and 52 as shown in Fig. 15 Then the collar 78 is fitted in place by inserting screw 64 through hole 82 and aligning holes 82 and 83 with slot 65, hole and either hole 58 or 59. The frame 70 of the adjustment assembly is then fit in position adjacent to the collar with its hole 71 aligned with hole 82 of the collar. With these parts in place the central'pivot pin 53 is fit in position and permanently secured therein by conventional means such as riveting and down into slot 67. 7

With these parts assembled, the center block 63 is given axial movement by pivoting Of'lhfi ,handles 51 and 52 according to the same principles as discussed above in the' parallel jaw embodiment. Accordingly opening of the jaws requires axial movement of the center block 63 relatively toward the jaw end of the pliers. This movement may be prevented by securing knurled nut 84, against the base 79 of the collar 78. It is thus seen that the nut and collar combine with center block 63 to provide the same'function in the pliers of this embodiment as does the combination of the nut, pin and centerblockof the parallel jaw pliers embodiment; namely, preventionof axial movement of the center block towardthe jawof the pliers. Therefore, in operation the guide pin 69 is pulled outward, the central pivot pin is secured within hole 58 or 59 depending upon whether closed or open adjustment is desired, and the guide pin 69 is inserted through the corresponding hole (either 61 or 62) and down into slot 67. p j

The pliers are thus operated to grip the work and the knurled nut 84 is screwed up against base 79 of collar 78. The pliers are now lodked securely on the work, and as stated above the nut may be cross drilled and have a pin inserted therein for providing additional locking pressure. It is thus apparent that I have providedfa simple yet rugged structure for locking pliers having two positions of adjustment. In addition, mystructure has the advantage ,offpreventing inadvertent changes. in position from one adjustment to the other. The offset pivot may also be extended to include more than two holes if desired. I

, It is also apparent that the center block 63 could be used in the parallel jaw embodiment of Figs. 1-8 by providing it with a pair of angularly-disposed grooves.

pivotal movement of the jaws and means in combination therewith to restrict the axial movement of the center .block with respect to the central pivot for providing the desired lock. V

In Fig. 16, there is shown a pair of wire-cutter pliers which embrace the generic form of this invention. Thus the pliers in Fig. 16 comprise handles 85 and 86 with jaws 87 and 88 integral therewith, and holes similar to the holes in handle 52 described in the two-position embodiment. In combination with these parts, there is a center block 89 similar to the center block 63 of Fig.

12, and a collar 90, similar to the collar 78 of Fig. 13.

The handles 85 and 86 have pins or lugs 91 and 92 fitting within the slots of the center block 89 and operating as described above- Nut 93 is fitted on to the threaded portion of center block 89 and screwed against a collar to provide the desired lock in the manner described for the pliers of Figs. 9-15 However, it should be noted that with the double-pivotal adjustment absent, the adjustment pin assembly shown in Fig. 14 is not required.

. Accordingly, the pliers of Fig. 16 illustrate that in its broad aspect, this invention provides a locking pliers with a small number of parts, and yet which has the ability to provide a tight clamping engagement whilebeing simple in operation.

What I claim is:

1. A pair of pliers comprising two jaws, a pair of crossed handles pivotally attached to each other and operatively connected to said, jaws for relative opening and crossing, in combination with a center block mounted on said pivot pin and movable thereon lengthwise of the pliers, said center block having a pair of angular-lydisposed slots, guide pins on said handles fitting in the slots'of the center-block and slidable therein on relative.

pivotal motion of the handles whereby pivotal motion of the handles is restricted by the axial motion of'the center 7 connecting the; handles at their crossing, in combination with a centerblock mounted on the pivot pin but movable lengthwise of the pliers and having angled straightline sliding contacts with theends of the jaws adjacent the block, said center block having a pair of angularlydisposed slots substantially parallel to said straight-line sliding contacts, means on said handles fitting in the slots of the center block and slidable-therein on relative pivotal l motion of the handles whereby pivotal motion of the hansaid center block, operative guide means on said dles slidably fitting the angularly disposed slot engage-f ment means on. said center block thereby ensuring. that the axial movement of said center block and the pivotal wedging motion of the two jaws together about the pivot pin are mutually dependent, and means for loekingthe center block against axial movement whereby opening pivotal movement of the handles andrel'ative opening of the jaws is prevented when said jaws are lockgripping a workpiece.

3. A pair of parallel jaw pliers comprising two jaws, a pair of crossed handles each pivotally attached to the forward end ofone of the jaws, and a pivot pin' hingedly connecting the handles at their crossing, in combination with a center block mounted on the pivot pin but movable lengthwise of the pliers and having angled straightline sliding contacts with the ends of the jaws adjacent the block, means controlled by the handles adjusting the axial movement of the center block relative to the position of the pivotal attachmentrof the jaws to the handles so that the jaws are kept parallel, and means on the center block adapted to lock the latter against axial movement whereby opening pivotal movementof the handles and relative opening of the jaws is prevented.

4. The pair of parallel jaw pliers defined in claim 3, inwhioh the means for locking the center block against axial movement comprises means abutting both the pivot pin and the center block.

5. A pair of parallel jaw pliers comprising two jaws, a pair of crossed handles each pivotally attached to the forward end of one of the jaws, and a pivot pin hingedly dles is restricted by the axial motion of the centerrblock, and means for locking the center block against axial movement whereby opening pivotal movement of the handles and relative opening of the jaws is prevented.

6. A- pair of pliers comprising two jaws, a pair. of

crossed handles pivotally attached to each other, ajaw being integrally formed at one end of each handle and a pivot pin hingedly connecting the handles at their crossing, in combination with a center block mounted on the pivot pin and movable thereon lengthwise of the pliers, said center block having a pair of angularly disposed slots, guide pins on said handles fitting in the slots of the center block and slidable therein on a relative pivotal movement of the handles, whereby pivotal motion of the handles is restricted by the axial motion of the center block, and means for locking the center block against axial movement, said locking means comprising a screw thread fixed with respect to the center block, a collar fitting over said screw thread and having flanges fitting around" the pivot pin, and an adjusting nut fitting over said screw thread and abutting said collar for positively restricting axial movement of said center block.

References Cited in the file of this patent UNITED STATES PATENTS 653,364 Pittaving July 10, 1900 988,656 Peck Apr. 4, 191.1 1,517,304 McNerney Dec. 2, 1924 2,063,532 Vertes Dec. 8, 1936 2,630,034 Bannister Mar. 3, 1953 2,687,661 Richardson Aug. 31, 1954 

